Im currently struggling to install DH on the 0.3.0 instance of ATM9.
Ive tried installing it with CurseForge via the add content tab. It seems to install the 2.1.2a version of DH which should be the right version for ATM9, but when I open up the client it starts loading, and then crashes.
Below is the crash report obtained by trying to open the client, and also a screenshot of the error message.